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1993 Ford E-350 hard at accelerating - engine fine?

02-22-2009, 06:11 PM

I have a 1993 Ford E350 with a 1 ton axle. It has a 460 motor in it. Just today, I drove it to town and on the way back, it wouldn't accelerate. I tried dropping it down to 2 and 1 but still the same problem. I just couldn't get past 25 mph, unless I was going down a hill. The engine could not rev up, it seem like it was about to shut off. It is difficult to get to 25 mph and even harder to stay at that speed.

When I shift it in neutral or park, the engine runs fine and revs up good.

When driving, the engine makes these 'popping' sounds as it seems it's about to shut off, all while trying to accelerate. Going up a hill, I got down to about 10mph and thought I wouldn't make it over the hill.

I'm a mechanic myself (not as a full time job) but this really surprised me, is it something with overdrive? Cat converter? why would this happen all of a sudden, no previous symptons/problems.

Any ideas?


02-22-2009, 10:34 PM
Try un-hooking the exhaust or removing the O2 sensors, and see if this helps.
Sounds like a plugged catalytic converter.

If no improvement try fuel pressure test 35-45 psi KOEO, 30-45 psi @ idle.
If possible monitor fuel pressure while driving.

Just some thoughts

02-25-2009, 10:11 AM
I will be taking it to the muffler shop today. I think it's the converter - how odd, it happened all of a sudden! It did have a lot of raw fuel run through it though, the shop put the wrong fuel pump on it the first time (a 80psi pump instead of the 30-40psi). It was getting 1-2 miles a gallon with a lot of black exhaust smoke!

I will pull the o2 sensor and drive it to the shop to see what happened.

02-26-2009, 10:24 AM
It is possible for a catalytic converter to 'suddenly' act as if its clogged. It happens when part of the matrix cracks free and gets lodge sideways or at an angle to the rest of the main flow through the converter. And besides old age, being overheated can cause the cracking - such as when the engine runs too rich....

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